This invention relates to photographic a camera, and more particularly to a camera of the type having an electromagnetically controllable shutter release actuator and in which the shutter tensioning mechanism is operatively connected to the film winding mechanism so that a predetermined motion of a common operating member serves both to advance the film through the space of one frame and to tension the shutter.
Cameras of the type described are known in the art, and in many of the prior art constructions, the motion of the common or single operating member is transmitted to the shutter tensioning mechanism through a swingable member constructed, for example, in the form of a lever. In such a motion transmitting lever arrangement, the dimensions of the lever must be excessively increased in order to insure that the shutter tensioning mechanism is fully operated for the tensioning of the shutter. This large size lever structure is incompatible with compact camera structures incorporating therein other various complicated mechanisms.
On the other hand, the shutter tensioning mechanism is associated with an electromagnet or a permanent magnet which is adapted to control the shutter release actuator so that when the shutter tensioning operation is terminated, the shutter is held in a tensioned position. During the course of this operation, the magnet is allowed to exert a force against the motion of the shutter tensioning mechanism which in turn increases the torque of the single operating member. In recently developed cameras and particularly single lens reflex cameras, the motion of the single operating member serves not only to control the operation of the film winding and shutter tensioning mechanism but also to control the mirror driving, diaphragm presetting and EE charging operations. In this respect, it is desirable to prevent the above-mentioned magnetic force from being applied to the single operating member through the film winding and shutter tensioning mechanism.